The United Kingdom Contribution to the AGARD 'Fatigue-Rated Fastener Systems' Programme
ROYAL AEROSPACE ESTABLISHMENT FARNBOROUGH (UNITED KINGDOM)
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This Report describes an investigation of the relative merits of a number of fastener systems. They are termed fatigue-rated fastener systems since they aim to enhance the fatigue endurance of the surrounding structure. Fatigue tests were performed on a number of laboratory specimens which simulated bolted connections in aircraft wing structures. It was shown that fastener systems incorporating hold cold expansion or fasteners installed with high interference fits were significantly superior to fasteners installed with a clearance fit in plain holes under the same test conditions. The longest fatigue endurances were observed in joints which contained fastener systems incorporating both cold expansion and a high degree of fastener interference. It was noted however, that cold expansion of fastener holes in asymmetric joints, with induced bending stresses, gave no increase in fatigue endurance over joints with fasteners installed in plain holes.